Thermal out-diffusion of H from undoped layers which had been grown by metalorganic vapour-phase epitaxy was investigated. The samples were grown by using dimethylzinc-triethylamine and di-tertiary butylselenide as precursors, with H and N as carrier gases. The typical atomic H content of the samples was 1018/cm3; which originated from pyrolysis products of the precursors. Incorporation from the carrier gas was negligible. Control samples which were grown by using molecular beam epitaxy exhibited no H incorporation. The out-diffusion process was investigated by using transient effusion methods. The results were explained in terms of diffusion-controlled effusion, which could be described by:

D (cm2/s) = 1.4 x 10-11 exp[-0.33(eV)/kT]

Hydrogen Effusion from Epitaxial ZnSe Layers B.Hahn, H.Preis, S.Blümel, W.Gebhardt: Applied Physics Letters, 1998, 73[11], 1556-8